Use 10.5 Disk Utility to restore 10.6.0 and Chameleon to USB thumbdrive

Use USB thumbdrive to install 10.6.0 and Chameleon to new disk partition

Use Apple Software Update to upgrade 10.6.0 disk partition to 10.6.*

Use Migration Assistant to import apps and data from 10.5 to 10.6.*

We used Lifehacker's snow-leopard-start-to-finish method. Compared to upgrading-in-place, thismethod safely preserves a parallel 10.5.* instance. In this guide, we use Chameleon to multi-boot (e.g. Linux, OSX 10.5, OSX 10.6, Windows). We also review data migration and hardware redundancy. We describe only our own experience with this hardware environment:

Migration (from 10.5 to 10.6.*)To avoid reinstalling non-vanilla applications (with all their associated settings/cookies/etc), we used Migration Assistant to import from a 10.5 Time Machine backup all except "Machine settings". This brought over everything except the eSATA host card driver from Silicon Image.